Balloon recovery apparatus



' July 2. 19 a D. L VI-:5 ANN 3,390,851

BALLOON RECOVERY APPARATUS 1 Filed Nov. 30, 1966 5 Sheets-Sheet 1 HIE:-

' INVENTOR. DENNIS LeVEE MANN his ATTORNEYS 2. 968 D. LE VEE MANN 3,390,851

4 BALLOON RECOVERY APPARATUS Filed Nov. 30. 1966 5 Sheets-Sheet 2 INVENTOR.

DENNIS LeVEE MANN his ATTORNEYS July 2. 1968 D. LE VEE MANN 3,

I BALLOON RECOVERY APPARATUS Filed Nov. 30, 1966 5 Sheets-Sheet :s

INVENTOR.

DENNIS LeVEE MANN' BY zif his ATTORNEYS July 2, 1968 0. LE VEE MANN 3,390,851

7 v BALLOON RECOVERY APPARATUS Filed Nov. 30, 1966 v 5 Sheets-Sheet 4 INVENTOR.

DENNIS LeVEE MANN I his AT T ORNE Y5 D. LE VEE MANN BALLOON RECOVERY APPARATUS July 2, 1968 5 Sheets-Sheet 5 Filed Nqv. 30. '1966 llllll JNVENTOR. DENNIS LeVEE MANN FIG. 70

his ATTORNEYS United States Patent 3,390,851 BALLOON RECOVERY APPARATUS Dennis LeVee Mann, Rockville, Md., assignor to Vitro Corporation of America, New York, N.Y., a corporation of Delaware Filed Nov. 30, 1966, Ser. No. 598,019 17 Claims. (Cl. 24432) ABSTRACT OF THE DISCLOSURE Large balloons, on the order of several million cu. ft. capacity, of the type used to carry aloft scientific equipment, experimental airborne devices, and other payloads are recovered for reuse with little or no damage by landing them with a protective encasement system which includes a flexible sleeve carried in a compact, inoperative condition during ascent and at altitude flight and is then progressively pulled over the deflated part of the balloon envelope as it is deflated and descends. Encasement proceeds by effecting relative movement between the sleeve and the deflated part of the envelope during descent. The balloon envelope is landed fully encased in the protective sleeve.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to apparatus for recovering, in substantially intact, reusable condition, the envelopes of balloons.

Large balloons, on the order of several million cubic feet capacity, are used to carry aloft scientific instruments, experimental high altitude equipment, various devices connected with the space exploration program, and other so-called payloads. These balloons range from relatively small sizes, say those having a volume of 1.6 million cubic feet which can carry a payload of roughly 900 lbs. to a float altitude of 100,000 ft., through a moderately largesized system capable of carrying a payload of over 9000 lbs. to 80,000 ft. and having a capacity aggregating over /2 million ft. (a launch balloon of over 250,000 cu. ft. capacity and a main balloon of 5,250,000 cu. ft. capacity) to the largest size balloon launched to date which has a capacity of 26,000,000 cu. ft., stands 800 ft. from the ground and is designed to carry a payload of 1700 lbs. to an altitude of 130,000 ft.

The balloons are constructed of various light-Weight, low-permeability materials (usually plastic film or plastic film with fabric reinforcing) which, even though they have relatively high tensile strength, are readily torn or ripped upon contact with the ground or objects on the ground such as rocks, trees, buildings and even heavy grass. Therefore, when the balloons are landed after operations have been completed, they are, even under the best of conditions, severely damaged and require repairs which can be nearly as costly as the initial fabrication costs. In many instances, the balloon envelope is so heavily damaged that it can not be repaired and reused. Even with the lesser costs made possible by recent improvements in the materials from which the balloons are made, such as scrim reinforced mylar or polyethylene, the balloons are still relatively expensive. To reduce the per flight costs of using balloons as vehicles for experimental and other operations above the earth, it would be of considerable advantage to be able to recover them with minimum damage to the envelope fabric so that they might be repaired, if necessary, and reused.

There is provided, in accordance with the invention, apparatus for recovering balloons of the type referred to above in a manner in which damage is substantially eliminated, or at least reduced to a minimum, thereby Patented July 2, 1968 making it possible to reuse the balloon. It is estimated that a cost-saving of one-third or more per flight is possible with the use of the recovery apparatus of the invention if a balloon can be reused at least four times. Even greater savings can be obtained as the number of balloon uses is increased.

The balloon recovery apparatus, according to the invention, comprises a protective casing which is carried aloft in a collapsed, compact form and is then progressively drawn over the deflated portion of the envelope as the flotation gas escapes during descent by elfecting movement of the sleeve along and relative to the deflated portion. In a preferred embodiment, the protective casing is located below the balloon and is arranged to move upwardly relative to the deflated portion of the balloon by retarding the descent of the casing with, for example, a parachute coupled to the upper part of the casing. As the balloon, preferably with the payload still connected to it, falls by gravity, the deflated portion pulls down through the casing and ultimately becomes completely encased in the casing. At this point or at some point close to full deflation, the payload can be released and seaprately landed by its own recovery parachute while the encased balloon is landed by the recovery system parachute. Alternatively, both the payload and the balloon envelope can be landed together by the recovery parachute.

In a preferred form, the recovery apparatus includes at its upper end, a rigid, hollow guide member, preferably of fustro-conical shape, which funnels the deflated envelope into the body of the casing. The recovery parachute canopy has a central opening and is joined at that opening to the upper end of the upper guide, the upper guide imparting the needed rigidity to the canopy opening when the envelope pulls down through it. The main body of the casing is a flexible sleeve, preferably of approximately the same length as the vertical dimension of the balloon. At the lower end of the sleeve is a lower rigid carrier frame which carries the flexible body and the upper guide during ascent and while the balloon is floating at altitude.

It is advantageous, though not necessary, to provide a two stage parachute, the first stage being deployed during the initial part of the descent and until the major portion of the balloon envelope is encased in the casing and the second stage being deployed during the final stages of balloon encasement and for landing. Such a twostage parachute can have two concentric toroidal canopy areas, the inner area having relatively shorter risers joined to the lower end of the upper rigid casing member and the outer canopy area having longer risers joined to a rigid ring secured to the flexible sleeve at a predetermined distance below the upper member such that the second canopy area will be deployed upon extension of the sleeve to a predetermined degree, such extension being a function of the extent to which encasement of the balloon envelope has proceeded.

It has been found in actual operations with the recovery apparatus of the invention that the balloon envelope ultimately became compacted in approximately the lower one-third of the casing. Advantageously, the lower section of the casing where the balloon becomes located for landing can be made of a more durable material while the upper section may be made of a less durable, lighter weight material, thereby saving weight, a factor which is of considerable importance in any device which is to be airborne. The two sections can be joined together in a manner which permits the upper section to be readily detached from the lower section, thereby facilitating handling at the landing site.

Although, as mentioned briefly above, the encased balloon envelope and the payload can be lowered to the ground as a unit by a single recovery para-chute, it may be advantageous to release the payload at some point during the descent of the balloon and payload system and lower it to the ground on its own parachute. In this case, it is desirable to release the balloon only at some predetermined point after substantial deflation of the balloon, inasmuch as the paritally inflated balloon contributes to the lift of the system. Release of the payload at the desired point during the deflation of the balloon can be effected by triggering a releasable coupling device between the balloon and the payload in response to a predetermined degree of extension of the casing sleeve; the degree of extension of the sleeve being a function of the degree of deflation of the balloon. In particular, the releasable coupling can be connected by a lanyard to a predetermined point on the recovery casing sleeve so that the lanyard is pulled when the sleeve has extended and the releasing device will uncouple and drop away the payload. In this system, the payload will, of course, have its own landing parachute.

For a better understanding of the invention, reference may be made to the following description of an exemplary embodiment, taken in conjunction with the figures of the accompanying drawings, in which:

FIG. 1 is a perspective view of the embodiment of the recovery apparatus in its stored position as the balloon is ascending or floating at altitude, most foreground portions of the apparatus being broken away to more clearly illustrate the apparatus;

FIG. 2 is a perspective view of the apparatus of FIG. 1 with the balloon partially deflated and encased during the initial part of the descent and recovery, foreground portions .of the apparatus again being broken away;

FIG. 3 is a perspective view, with foreground parts broken away, of the apparatus as it appears during the final stage of descent, the balloon being fully encased and it and the payload being separately parachuted to earth;

FIG. 4 is a perspective view of the upper rigid casing guide member and a portion of the flexible sleeve;

FIG. 5 is a perspective view of the lower rigid carrier frame of the apparatus, other parts of the apparatus being shown in phantom lines in stored positions;

FIG. 6 is a view of another form of the lower rigid carrier frame; and

FIGS. 7A to 7D are pictorial views showing, in sequence, the overall operation of the system.

Referring to FIGS. 1 to 3, and 7A to 7D, the two basic components of any balloon system of the type with which the recovery apparatus of the invention is employed are the balloon envelope 10, of which only the lower portion is shown in FIGS. 1 and 2, and the payload 12. The envelope is usually made of polyethylene or of polyethylene or mylar reinforced with a fabric or net of fine threads known as scrim. As mentioned previously, the recovery system of the invention, with suitable dimensional and structural modifications, can be used with balloons of most any size, the basic principles of the invention being broadly applicable. The payload 12 is suspended in a manner to be described below from the lower fitting 14 on the balloon. The balloon conventionally includes a gas inlet at its upper end (not shown) and a valve (not shown) that can be operated from the ground to release gas from the balloon to reduce its lift and land it. As is well known to those skilled in the art, a predetermined quantity of lift gas, usually helium, is introduced into the balloon envelope, thus expanding it to a small fraction of its ultimate volume (see FIG. 7A). The major part of the balloon envelope remains deflated but gradually inflates as the balloon ascends to higher altitudes and the helium expands. At float altitude, the balloon is substantially fully expanded (see FIG. 7B).

As a matter of terminology, the term balloon generally refers to the inflated body including envelope and gas, whereas balloon envelope .or envelope are used to refer to the plastic or fabric enclosure alone. In either case, the reference numeral 10 will be employed here.

The recovery apparatus, which is designated generally by the reference numeral 20, is located in a relatively short vertical space (short as compared to the balloon system height) between the balloon 10 and the payload 12 during the takeoff, ascent and fully inflated, floating-av elevation phases of the balloon flight, asshown in FIG. 1. The major components of the recovery apparatus 20 are a rigid lower carrier frame 22 which is coupled to the balloon lower fitting 14 by a suitable connector 24, a flexible sleeve 26 having its lower end joined to the frame 22, a hollow upper rigid guide member 28 joined to the upper end of the sleeve, and a parachute 30 associated with the upper portion of the recovery apparatus. In the embodiment illustrated in the drawings, the payload is landed by a separate parachute 32, but during takeoff, ascent, flight and a part of the descent of the balloon, the payload parachute 32 is suspended directly from the rigid lower carrier 22 and in turn supports the payload through the payload parachute risers.

Referring particularly to FIG. 5, the lower rigid carrier 22, in one form, is composed of a vertical cage 34 con stituted by three vertical members 36 reinforced laterally by diagonal members 38, an upper ring 40 and three base members 42, each of which has an outwardly extending end portion 42a terminating in an upwardly extending leg 42b. A ring 43 is attached to the ends of the legs 42b. Near the upper end of the vertical cage 34, is the connector 24 to which the lower balloon fitting 14 (FIG. 1) is fastened. .Also secured to the connector 24 is a rod or cable 46 carrying a releasable coupling device 48 to which the payload parachute 32 is attached and by which, therefore, the payload 12 is supported. The coupling device 48 may be of a type adapted to release the payload parachute in response to a signal from the ground or, preferably, in response to some predetermined occurrence during the flight of the balloon. A preferred payload release sequence will be described below.

FIG. 6 shows another form for the carrier. In this embodiment, the carrier is made up of a main vertical section 102 constituted by U-shaped members 104 and 106 having a coupling fitting 108 at the upper end. The lower ends of the members 104- and 106 are joined to four outwardly extending base members 110. A lower ring 112 having a diameter somewhat larger than the lower end of the upper member 28 is attached to the extremities of the base members. It is apparent that the structure and operation of the alternative embodiment of the carrier shown in FIG. 6 are generally in conformity with the embodiment of FIG. 5.

Laced to the carrier 22 near the upper end of the vertical cage 34 is the lower end of the flexible sleeve 26. The sleeve is preferably made of a smooth, durable fabric, such as nylon, inasmuch as one of its main purposes is to protect the balloon envelope material. In a preferred form, as shown best in FIG. 3, the sleeve is formed in two parts, the lower part 26a making up approximately onethird of the total casing length or such other portion which will be determined to be adequate to fully envelope the balloon when it reaches the ground and being made of a relatively more durable material, such as a nylon fabric coated with polyethylene to render it stronger and moisture impervious. The upper sleeve section 26b may be made of nylon fabric alone or some other less durable, lighter weight material and is laced to the lower section 26a in a manner which will permit the two sections to .be disconnected quickly and easily at the landing site. The

total length of the fabric sleeve is preferably approxi mately equal to the vertical dimension of the balloon envelope.

Referring to FIG. 4, the upper end of the sleeve 26 is either laced to the lower end of the rigid upper guide member 28 or extends up through the guide (as shown) and is joined to the upper end. In the former case, the

guide 28 will include its own inner lining which may, for example, be nylon fabric. The guide 28 is a rigid frame of suitable structure, such as an assembly of lightweight longitudinal and circumferential tubing sections 28a and 28b defining a hollow cage, preferably frustoconical in shape with the upper end being the larger end and the lower end being the same diameter as the sleeve.

As shown in FIG. 1, the recovery apparatus 20 is stored in a compact, relatively short vertical space between the balloon and payload 12 during the ascent and ataltitude flight of the balloon. The lower part of the fabric sleeve 26 is folded into the top part of the carrier frame 22 and the rest of the sleeve is folded into the lower part of the space between the vertical section 34 of the frame 22 and the upper guide 28. The guide 28 is supported and held in position by the outwardly extending portions and legs 42a and 42b of the lower members 42 and by the ring 43 of the carrier 22.

When the flight mission is completed and the balloon and payload are to be landed, the signals appropriate to initiate deflation of the balloon by opening its gas valve or operating the quick deflate mechanism are given and the lifting gas begins to escape, thereby initiating descent. Referring to FIG. 2, the balloon envelope 10 is pulled downwardly by its weight and that of the payload. Meanwhile, the downward movement of the upper part of the sleeve is retarded with respect to the balloon and payload so that the deflated part of the balloon envelope slides down into the sleeve. In the illustrated embodiment, the upward movement of the sleeve relative to the thendeflated part of the balloon is afforded by the parachute 30. Although a parachute having a single canopy section can be used, it is advantageous to provide a two-stage parachute which, as best shown in FIG. 3, is in the form of separately deployable, inner and outer semi-toroidal canopy sections 30a and 30b. The inner toroidal canopy section 30a has a central opening 49 which is of the same dimension as the upper end of the guide 28 and is laced to it; the same lacing can be employed to secure the sleeve 26 to the guide 28. The risers 50 of the inner canopy section 30a are relatively short and are tied off near the lower end of guide 28, holes 51 being provided in the sleeve 26 (FIG. 4) so that the sleeve 26 can be tied to the guide by the risers. The inner margin of the outer canopy section 30b is joined to the outer margin of the inner section and its risers 52 are joined to a ring 54 sewed into the upper sleeve section 26b at a predetermined distance below the guide 28.

The inner canopy section 30a of the parachute 30 deploys upon downward movement of the balloon as the lift gas is released and the balloon descends. Meanwhile, the outer canopy sections 30b flies free, as shown in FIG. 2, inasmuch as its risers 52 are not brought into tension until after a predetermined degree of extension of the sleeve 26 takes place. Because the upper guide 28 is retarded by the parachute in its downward movement relative to the balloon, which is dropping due to its own weight and the weight of the payload, the guide and sleeve are drawn up along the deflated portion of the envelope 10 at a rate corresponding generally to the rate of deflation of the envelope. In other words, as the lift gas escapes from the balloon, the lower part of the balloon envelope becomes flaccid and is able to be gathered into a relatively small diameter by the guide 28 and to be guided down into the sleeve. The progressive gathering in and ensleevement of the balloon continues until the major part is enveloped within the sleeve, preferably when the lifting capability of the balloon is reduced to an extent that it does not provide significant support for the payload. At that point the payload is released by actuating the releasable coupling device 48.

An effective way of releasing the payload is to trigger the releasable coupling when a predetermined part of the sleeve has been extended, the degree of extension of the sleeve being indicative of the degree of deflation of the balloon 10. To this end, a lanyard 56 (see FIG. 2 or 3) is connected to a part of the sleeve and to the coupling device so that when tension is placed on the lanyard upon extension of the sleeve, the release coupling is triggered to drop the payload. Meanwhile during the descent of the system, the payload parachute has been furled by being reefed with lines 58, the reefing being coupled by another lanyard 60 joined to the lower frame 22. When the payload and its parachute drop, the lanyard 58 pulls the reefing lines 58 clear of the payload parachute, thereby permitting the payload parachute to be deployed, as illustrated in FIG. 3, to lower the payload to the ground at a safe landing velocity.

During part of the descent phase, the still partially inflated balloon carries a share of the system weight; in particular, the payload 12, the payload parachute 32 and the lower carrier are supported predominantly by the balloon. At the same time, the inner canopy section 30a of the recovery parachute 30 may support some of the load of the aforementioned parts by engagement of the upper member 28 with the balloon envelope but, predominantly, supports the upper part of the sleeve and the upper guide 28. The load carried by the parachute is relatively low, as compared to the load supported by the balloon, during the initial phase of descent. However, the load on the parachute gradually increases as the balloon deflates and its lifting ability is correspondingly decreased. At some point during the descent the load on the parachute becomes suflicient to deploy the second parachute section 30b as the downward force on the lower parts of the casing becomes suflicient to exert a pull on the risers of the second parachute section. Until that point is passed, the second section flies free in the manner shown in FIG. 2 and as mentioned above. Thereafter, the entire parachute 30, i.e., both toroidal canopy sections, are deployed and float the deflated balloon envelope in sleeved position to the ground. Inasmuch as the risers 52 of the second parachute section carry only the weight of the sleeve portion below their point of attachment until the sleeve is nearly fully extended, deployment of the second stage will not take place until after substantially all of the balloon envelope is deflated. When deflation is complete, the sleeve becomes fully extended, inasmuch as it carries the load of the deflated balloon envelope and the lower parts of the recovery system, as shown in FIG. 3.

After ensleevement of the balloon envelope and during the final stage of descent, the envelope has been found to gravitate to the lower one-third section of the sleeve 26 (FIG. 3). As pointed out above, the lower one-third section 26a of the sleeve 26 is preferably made of plasticcoated nylon, a material found to be highly resistant to damage when the system is landed, thereby protecting the balloon envelope. After landing, a recovery team can readily separate the upper two-thirds section 26b of the sleeve along with the parachute 30 and upper member 28 leaving the envelope encapsulated in the lower one-third section 26a. The ensleeved envelope 10, still protected by the sleeve section 26a, can then be loaded into a truck and transported intact to a repair station for unpacking and any necessary repairs or replacements of such parts as the gas valve or any quick deflating apparatus.

One further feature of the operation of the recovery apparatus should be mentioned. It is that it operates automatically to progressively encase the deflated portion of the envelope of the balloon whenever it descends and deflates, there being no need for radio command or sequence control of recovery stages. If the balloon should change from a descent mode to an ascent mode, the balloon upon reinflation will withdraw itself from the sleeve to the extent necessary, the latter returning even to its initial, stored condition. Upon resumption of descent, the recovery apparatus will automatically operate in the abovedescribed manner. It should be noted that only two release devices are employed in the descent and safe recovery of the system, one to release the payload from the balloon envelope at a predetermined point during descent and the other to unfurl the recovery parachute by releasing its reefing lines.

In addition to enabling the reuse of the balloon, it is clear that the recovery apparatus itself can generally be reused, perhaps after minor repairs. As a further advantage, the sleeve provides an appropriate shipping container for returning the encased balloon envelope after recovery for inspection and repair without further handling at the impact site. The recovery apparatus is of relatively light weight, thereby providing the important economic advantage of alfording reuse of the balloon envelope with a minimum increase in system weight and cost. Generally, the recovery apparatus will weigh something close to 10% of the main balloon weight. The cost of providing an increased balloon capacity to accommodate the weight of the recovery apparatus is but a fraction of the possible savings in cost afforded by reuse of the system.

It will be understood that the embodiment of the invention described above and shown in the drawings is merely exemplary; those skilled in the art will be able to make numerous variations and modifications of it without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as defined in the appended claims.

I claim:

1. Apparatus for recovering an inflatable balloon envelope comprising a flexible elongated protective casing means carried by the balloon in a normally inactive position when the balloon is being inflated or is afloat for receiving the envelope as the balloon is deflated, and aerodynamic retarding means for producing relative movement between the envelope and the protective casing means during deflation of the balloon to encase the envelope within said casing means for protecting it during landing.

2. Apparatus according to claim 1 wherein the casing means includes an elongated sleeve of flexible material, the sleeve being collapsed into a relatively short length when inactive and being extended along and about the envelope when said envelope is deflated.

3. Apparatus according to claim 2 wherein the casing means includes a rigid section to which one end of the sleeve is attached for guiding the envelope into the sleeve upon the said relative displacement.

4. Apparatus according to claim 3 wherein the combined length of the rigid section and the sleeve is substantially equal to the major dimension of the balloon.

5. Apparatus according to claim 4 further comprising a rigid frame attached to the balloon and positioned to receive the protective casing when it is in its inactive position.

6. Apparatus for recovering an inflatable balloon envelope of light-weight, low permeability material of the type adapted to lift and float a payload assembly comprising protective casing means normally carried below the balloon in an inactive position when the balloon is rising or afloat and encompassing the deflated envelope to protect it upon landing, the casing means including an elongated sleeve of flexible material which is collapsible into a relatively short length when inactive and extendable along and about the envelope to fully encompass it when the balloon is landed, rigid guide means attached to the upper end of the sleeve for guiding the envelope progres sively into the sleeve as it is deflated and the deflated portion is displaced into the sleeve, rigid carrier means attached to the balloon envelope to receive the sleeve when it is in its inactive position, and means coupled to the upper end of the sleeve to retard its downward movement relative to the descent of the balloon and effect upward movement of the sleeve relative to the envelope to progressively encase the envelope as it deflates.

7. Apparatus according to claim 6 wherein the means for producing relative displacement between the protective casing and the envelope is a parachute.

8. Apparatus according to claim 7 wherein the parachute has a central opening forre'ceiving the'deflated portion of the envelope therethrough, the parachute, when deployed during descent of the balloon, being displaced upwardly along the deflated portion of the balloon envelope and extending the protective casing about and relative thereto.

9. Apparatus according to claim 8 wherein the parachute includes two concentric semi-toroidal canopy areas, and means for first deploying one of said areas alone for displacement of the sleeve to substantially fully encase the balloon envelope, and for thereafter deploying the second area in addition to the first for landing of the encased envelope.

10. Apparatus according to claim 9 wherein the two areas are concentric, and in which the first area has the circular opening, the parachute fabric adjacent the opening being attached to one portion of the rigid guide section and the outer perimeter of the first area being attached to another portion of the rigid guide by relatively short lines.

11. Apparatus according to claim 10 wherein the second area has an inner perimeter coinciding with the outer perimeter of the first area, and the outer perimeter of the second area is attached to thesleeve by relatively longer lines for substantially greater deployment of the second area, the second area being deployed only upon extension of the sleeve to a predetermined degree.

12. A system according to claim 11 in which a rigid ring is mounted on the sleeve substantially below the rigid guide and in which the longer lines are attached to the ring.

13. Apparatus according to claim 6 further comprising means coupled to the payload for carrying it safely to the ground separately from the balloon envelope, and means releasably coupling the payload to the balloon.

14. Apparatus according to claim 13 further comprising means for actuating the releasable coupling upon a predetermined degree of encasement of the balloon envelope.

15. Apparatus according to claim 13 wherein the means for separately carrying the payload to the ground is a parachute, wherein the payload is releasably coupled to the balloon through the payload parachute and the rigid carrier means, and further comprising releasable reefing means for preventing the payload parachute from opening until the payload is released from the balloon envelope.

16. Apparatus according to claim 6 wherein the flexible elongated sleeve includes first and second longitudinal sections, the first sec-tion constituting the lower part of the sleeve and having a length suflicient to substantially entirely enca-se the deflated balloon envelope when it is landed and the second section being located above the first section, and further comprising means releasably joining the first and second sections together in a manner facilitating disconnection of the sections from each other when theencased balloon envelope is recovered after landing.

17. Apparatus for recovering an inflatable balloon envelope of light-weight, low permeability material and of the type adapted to lift and float a payload comprising rigid carrier means attached to a lower part of the balloon envelope, an elongated flexible sleeve having its lower end joined to the carrier, rigid guide means attached to the upper end of the sleeve for guiding the balloon envelope progressively into the sleeve as it deflates, the carrier means being formed to support the guide means during the ascent and flight of the balloon and the flexible sleeve being receivable in a folded, inactive condition on the carrier, and a parachute having a central opening and joined at that opening to the upper end of the guide, the parachute being deployable upon downward movement of the balloon to afford relative upward movement of the guide and flexible sleeve progressively along and relative 9 10 to the deflated portion of the balloon envelope as the 3,151,824 10/1964 Struble 24431 envelope descends upon release of the lifting gas. 3,168,266 2/1965 Yost- 24431 X References Cited FERGUS S. MIDDLETON, Primary Examiner.,

UNITED STATES PATENTS 5 MILTON BUCHLER, Examiner.

2,635,835 4/1953 Dungan et a1. 244-31 T A O Assistant Examiner 3,110,457 11/1963 Struble 244-31 

